.TH "Error handling" 3 "7 Oct 2009" "Version 1.0" "BrlAPI" \" -*- nroff -*-
.ad l
.nh
.SH NAME
Error handling \- How to handle errors.  

.PP
.SS "Data Structures"

.in +1c
.ti -1c
.RI "struct \fBbrlapi_error_t\fP"
.br
.in -1c
.SS "Defines"

.in +1c
.ti -1c
.RI "#define \fBBRLAPI_ERROR_SUCCESS\fP   0"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_NOMEM\fP   1"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_TTYBUSY\fP   2"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_DEVICEBUSY\fP   3"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_UNKNOWN_INSTRUCTION\fP   4"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_ILLEGAL_INSTRUCTION\fP   5"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_INVALID_PARAMETER\fP   6"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_INVALID_PACKET\fP   7"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_CONNREFUSED\fP   8"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_OPNOTSUPP\fP   9"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_GAIERR\fP   10"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_LIBCERR\fP   11"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_UNKNOWNTTY\fP   12"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_PROTOCOL_VERSION\fP   13"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_EOF\fP   14"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_EMPTYKEY\fP   15"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_DRIVERERROR\fP   16"
.br
.ti -1c
.RI "#define \fBBRLAPI_ERROR_AUTHENTICATION\fP   17"
.br
.ti -1c
.RI "#define \fBbrlapi_error\fP   (*brlapi_error_location())"
.br
.ti -1c
.RI "#define \fBbrlapi_errno\fP   (brlapi_error.brlerrno)"
.br
.ti -1c
.RI "#define \fBbrlapi_libcerrno\fP   (brlapi_error.libcerrno)"
.br
.ti -1c
.RI "#define \fBbrlapi_gaierrno\fP   (brlapi_error.gaierrno)"
.br
.ti -1c
.RI "#define \fBbrlapi_errfun\fP   (brlapi_error.errfun)"
.br
.in -1c
.SS "Typedefs"

.in +1c
.ti -1c
.RI "typedef uint32_t \fBbrlapi_packetType_t\fP"
.br
.ti -1c
.RI "typedef void(BRLAPI_STDCALL * \fBbrlapi_exceptionHandler_t\fP )(int error, \fBbrlapi_packetType_t\fP type, const void *packet, size_t size)"
.br
.ti -1c
.RI "typedef void(BRLAPI_STDCALL * \fBbrlapi__exceptionHandler_t\fP )(\fBbrlapi_handle_t\fP *handle, int error, \fBbrlapi_packetType_t\fP type, const void *packet, size_t size)"
.br
.in -1c
.SS "Functions"

.in +1c
.ti -1c
.RI "void BRLAPI_STDCALL \fBbrlapi_perror\fP (const char *s)"
.br
.ti -1c
.RI "\fBbrlapi_error_t\fP *BRLAPI_STDCALL \fBbrlapi_error_location\fP (void)"
.br
.ti -1c
.RI "const char *BRLAPI_STDCALL \fBbrlapi_strerror\fP (const \fBbrlapi_error_t\fP *error)"
.br
.ti -1c
.RI "const char *BRLAPI_STDCALL \fBbrlapi_getPacketTypeName\fP (\fBbrlapi_packetType_t\fP type)"
.br
.ti -1c
.RI "int BRLAPI_STDCALL \fBbrlapi_strexception\fP (char *buffer, size_t bufferSize, int error, \fBbrlapi_packetType_t\fP type, const void *packet, size_t packetSize)"
.br
.ti -1c
.RI "int BRLAPI_STDCALL \fBbrlapi__strexception\fP (\fBbrlapi_handle_t\fP *handle, char *buffer, size_t bufferSize, int error, \fBbrlapi_packetType_t\fP type, const void *packet, size_t packetSize)"
.br
.ti -1c
.RI "\fBbrlapi_exceptionHandler_t\fP BRLAPI_STDCALL \fBbrlapi_setExceptionHandler\fP (\fBbrlapi_exceptionHandler_t\fP handler)"
.br
.ti -1c
.RI "\fBbrlapi__exceptionHandler_t\fP BRLAPI_STDCALL \fBbrlapi__setExceptionHandler\fP (\fBbrlapi_handle_t\fP *handle, \fBbrlapi__exceptionHandler_t\fP handler)"
.br
.ti -1c
.RI "void BRLAPI_STDCALL \fBbrlapi_defaultExceptionHandler\fP (int error, \fBbrlapi_packetType_t\fP type, const void *packet, size_t size)"
.br
.ti -1c
.RI "void BRLAPI_STDCALL \fBbrlapi__defaultExceptionHandler\fP (\fBbrlapi_handle_t\fP *handle, int error, \fBbrlapi_packetType_t\fP type, const void *packet, size_t size)"
.br
.in -1c
.SS "Variables"

.in +1c
.ti -1c
.RI "const char * \fBbrlapi_errlist\fP []"
.br
.ti -1c
.RI "const int \fBbrlapi_nerr\fP"
.br
.ti -1c
.RI "\fBbrlapi_error_t\fP \fBbrlapi_error\fP"
.br
.ti -1c
.RI "int \fBbrlapi_errno\fP"
.br
.ti -1c
.RI "int \fBbrlapi_libcerrno\fP"
.br
.ti -1c
.RI "int \fBbrlapi_gaierrno\fP"
.br
.ti -1c
.RI "const char * \fBbrlapi_errfun\fP"
.br
.in -1c
.SH "Detailed Description"
.PP 
When a function fails, \fBbrlapi_errno\fP will hold an error code to explain why it failed. It should always be reported somehow.
.PP
Although most errors are reported that way, some (called exceptions) are reported asynchronously for efficiency reasons, because they always just report a programming error. The affected functions are: brlapi_setFocus, brlapi_write* and brlapi_sendRaw. When they happen, the next call to brlapi_something will close the connection and call the \fIexception\fP handler. If the exception handler returns, the brlapi_something function will return an end-of-file error.
.PP
The default exception handler (\fBbrlapi_defaultExceptionHandler()\fP) dumps the guilty packet before abort()ing. It can be replaced by calling \fBbrlapi_setExceptionHandler()\fP. For instance, the Java and Python bindings use this for raising a Java or Python exception that may be caught. 
.SH "Define Documentation"
.PP 
.SS "#define \fBbrlapi_errfun\fP   (brlapi_error.errfun)"
.PP
Cheat about the brlapi_errfun C token 
.SS "#define \fBbrlapi_errno\fP   (brlapi_error.brlerrno)"
.PP
Cheat about the brlapi_errno C token 
.SS "#define \fBbrlapi_error\fP   (*brlapi_error_location())"
.PP
Cheat about the brlapi_error C token 
.SS "#define BRLAPI_ERROR_AUTHENTICATION   17"
.PP
Authentication failed 
.SS "#define BRLAPI_ERROR_CONNREFUSED   8"
.PP
Connection refused 
.SS "#define BRLAPI_ERROR_DEVICEBUSY   3"
.PP
A connection is already using RAW or suspend mode 
.SS "#define BRLAPI_ERROR_DRIVERERROR   16"
.PP
Packet returned by driver too large 
.SS "#define BRLAPI_ERROR_EMPTYKEY   15"
.PP
Key file empty 
.SS "#define BRLAPI_ERROR_EOF   14"
.PP
Unexpected end of file 
.SS "#define BRLAPI_ERROR_GAIERR   10"
.PP
Getaddrinfo error 
.SS "#define BRLAPI_ERROR_ILLEGAL_INSTRUCTION   5"
.PP
Forbiden in current mode 
.SS "#define BRLAPI_ERROR_INVALID_PACKET   7"
.PP
Invalid size 
.SS "#define BRLAPI_ERROR_INVALID_PARAMETER   6"
.PP
Out of range or have no sense 
.SS "#define BRLAPI_ERROR_LIBCERR   11"
.PP
Libc error 
.SS "#define BRLAPI_ERROR_NOMEM   1"
.PP
Not enough memory 
.SS "#define BRLAPI_ERROR_OPNOTSUPP   9"
.PP
Operation not supported 
.SS "#define BRLAPI_ERROR_PROTOCOL_VERSION   13"
.PP
Bad protocol version 
.SS "#define BRLAPI_ERROR_SUCCESS   0"
.PP
Success 
.SS "#define BRLAPI_ERROR_TTYBUSY   2"
.PP
A connection is already running in this tty 
.SS "#define BRLAPI_ERROR_UNKNOWN_INSTRUCTION   4"
.PP
Not implemented in protocol 
.SS "#define BRLAPI_ERROR_UNKNOWNTTY   12"
.PP
Couldn't find out the tty number 
.SS "#define \fBbrlapi_gaierrno\fP   (brlapi_error.gaierrno)"
.PP
Cheat about the brlapi_gaierrno C token 
.SS "#define \fBbrlapi_libcerrno\fP   (brlapi_error.libcerrno)"
.PP
Cheat about the brlapi_libcerrno C token 
.SH "Typedef Documentation"
.PP 
.SS "typedef void(BRLAPI_STDCALL * \fBbrlapi__exceptionHandler_t\fP)(\fBbrlapi_handle_t\fP *handle, int error, \fBbrlapi_packetType_t\fP type, const void *packet, size_t size)"
.PP
.SS "typedef void(BRLAPI_STDCALL * \fBbrlapi_exceptionHandler_t\fP)(int error, \fBbrlapi_packetType_t\fP type, const void *packet, size_t size)"
.PP
Types for exception handlers
.PP
Types of exception handlers which are to be given to \fBbrlapi_setExceptionHandler()\fP and \fBbrlapi__setExceptionHandler()\fP.
.PP
\fBParameters:\fP
.RS 4
\fIhandle\fP is the handle corresponding to the guilty connection; 
.br
\fIerror\fP is a BRLAPI_ERROR_ error code; 
.br
\fItype\fP is the type of the guilty packet; 
.br
\fIpacket\fP points to the content of the guilty packet (might be a little bit truncated); 
.br
\fIsize\fP gives the guilty packet's size. 
.RE
.PP

.SS "typedef uint32_t \fBbrlapi_packetType_t\fP"
.PP
Type for packet type. Only unsigned can cross networks, 32bits 
.SH "Function Documentation"
.PP 
.SS "void BRLAPI_STDCALL brlapi__defaultExceptionHandler (\fBbrlapi_handle_t\fP * handle, int error, \fBbrlapi_packetType_t\fP type, const void * packet, size_t size)"
.PP
.SS "\fBbrlapi__exceptionHandler_t\fP BRLAPI_STDCALL brlapi__setExceptionHandler (\fBbrlapi_handle_t\fP * handle, \fBbrlapi__exceptionHandler_t\fP handler)"
.PP
.SS "int BRLAPI_STDCALL brlapi__strexception (\fBbrlapi_handle_t\fP * handle, char * buffer, size_t bufferSize, int error, \fBbrlapi_packetType_t\fP type, const void * packet, size_t packetSize)"
.PP
.SS "void BRLAPI_STDCALL brlapi_defaultExceptionHandler (int error, \fBbrlapi_packetType_t\fP type, const void * packet, size_t size)"
.PP
.SS "\fBbrlapi_error_t\fP* BRLAPI_STDCALL brlapi_error_location (void)"
.PP
Get per-thread error location
.PP
In multithreaded software, \fBbrlapi_error\fP is thread-specific, so api.h cheats about the brlapi_error token and actually calls \fBbrlapi_error_location()\fP.
.PP
This gets the thread specific location of global variable \fBbrlapi_error\fP 
.SS "const char* BRLAPI_STDCALL brlapi_getPacketTypeName (\fBbrlapi_packetType_t\fP type)"
.PP
Get plain packet type
.PP
\fBbrlapi_getPacketTypeName()\fP returns the plain packet type name corresponding to its argument. 
.SS "void BRLAPI_STDCALL brlapi_perror (const char * s)"
.PP
Print a BrlAPI error message
.PP
\fBbrlapi_perror()\fP reads \fBbrlapi_error\fP, and acts just like perror(). 
.SS "\fBbrlapi_exceptionHandler_t\fP BRLAPI_STDCALL brlapi_setExceptionHandler (\fBbrlapi_exceptionHandler_t\fP handler)"
.PP
Set a new exception handler
.PP
\fBbrlapi_setExceptionHandler()\fP replaces the previous exception handler with the handler parameter. The previous exception handler is returned to make chaining error handlers possible.
.PP
The default handler just prints the exception and abort()s. 
.SS "const char* BRLAPI_STDCALL brlapi_strerror (const \fBbrlapi_error_t\fP * error)"
.PP
Get plain error message
.PP
\fBbrlapi_strerror()\fP returns the plain error message corresponding to its argument. 
.SS "int BRLAPI_STDCALL brlapi_strexception (char * buffer, size_t bufferSize, int error, \fBbrlapi_packetType_t\fP type, const void * packet, size_t packetSize)"
.PP
Describes an exception
.PP
\fBbrlapi_strexception()\fP puts a text describing the given exception in buffer.
.PP
The beginning of the guilty packet is dumped as a sequence of hex bytes.
.PP
\fBReturns:\fP
.RS 4
the size of the text describing the exception, following snprintf()'s semantics. 
.RE
.PP

.SH "Variable Documentation"
.PP 
.SS "const char* \fBbrlapi_errfun\fP"
.PP
Shorthand for brlapi_error.errfun 
.SS "const char* \fBbrlapi_errlist\fP[]"
.PP
Error message list
.PP
These are the string constants used by \fBbrlapi_perror()\fP. 
.SS "int \fBbrlapi_errno\fP"
.PP
Shorthand for brlapi_error.errno 
.SS "\fBbrlapi_error_t\fP \fBbrlapi_error\fP"
.PP
Global variable brlapi_error
.PP
\fBbrlapi_error\fP is a global left-value containing the last error information. Its errno field is not reset to BRLAPI_ERROR_SUCCESS on success.
.PP
This information may be copied in \fBbrlapi_error_t\fP variables for later use with the brlapi_strerror function. 
.SS "int \fBbrlapi_gaierrno\fP"
.PP
Shorthand for brlapi_error.gaierrno 
.SS "int \fBbrlapi_libcerrno\fP"
.PP
Shorthand for brlapi_error.libcerrno 
.SS "const int \fBbrlapi_nerr\fP"
.PP
Number of error messages